Two devices in the same network, but not same subnetwork

I have 2 Ubuntu systems in the same network. IP A is 149.201.37.66 and IP B is 149.201.55.106

I want to use a tool, which needs both systems to be in the same subnet: AAA.BBB.CCC.xxx.

I can ping both devices from each other, I just need them to be in the same subnetwork. I can’t change the original IP manually, it is a DHCP. But is there a way to create my own sub network to have both systems in the same IP range?

I am using Ubuntu 18.04